Hume: A Domain-Specific Language for Real-Time Embedded Systems

This paper describes Hume: a novel domain-specific language whose purpose is to explore the expressibility/costability spectrum in resource-constrained systems, such as real-time embedded or control systems. Hume provides a number of high level features including higherorder functions, polymorphic types, arbitrary but sized user-defined data structures, asynchronous processes, lightweight exception handling, automatic memory management and domain-specific metaprogramming features, whilst seeking to guarantee strong space/time behaviour and maintaining overall determinacy. 1 Essential Language Properties in the Real-Time Embedded System Domain Embedded systems are becoming increasingly prevalent in everyday life. From a computer science perspective such systems represent a software/hardware blend at a much lower level of abstraction than usual. They also introduce strict costdriven requirements on system capabilities. Adapting general purpose languages for such a domain often leads to a poor fit between the language features and the implementation requirements. Domain-specific language designs such as Hume allow low-level system requirements to guide the design of the high level language features we desire. We can identify a number of essential or desirable properties for a language that is aimed at real-time embedded systems [20]. – determinacy – the language should allow the construction of determinate systems, by which we mean that under identical environmental constraints, all executions of the system should be observationally equivalent ; This work is generously supported by a grant from the UK’s Engineering and Physical Sciences Research Council. F. Pfenning and Y. Smaragdakis (Eds.): GPCE 2003, LNCS 2830, pp. 37–56, 2003. c © Springer-Verlag Berlin Heidelberg 2003 38 Kevin Hammond and Greg Michaelson data structures Full Hume